import boto3
from botocore.exceptions import ClientError
from typing import BinaryIO
from app.storage.base import StorageBackend
from app.config import settings
import logging

logger = logging.getLogger(__name__)


class S3Backend(StorageBackend):
    """AWS S3 storage backend implementation"""

    def __init__(self):
        self.s3_client = boto3.client(
            's3',
            aws_access_key_id=settings.aws_access_key_id,
            aws_secret_access_key=settings.aws_secret_access_key,
            region_name=settings.aws_region
        )
        self.bucket_name = settings.s3_bucket_name
        self._ensure_bucket_exists()

    def _ensure_bucket_exists(self):
        """Create bucket if it doesn't exist"""
        try:
            self.s3_client.head_bucket(Bucket=self.bucket_name)
        except ClientError as e:
            error_code = e.response['Error']['Code']
            if error_code == '404':
                try:
                    self.s3_client.create_bucket(
                        Bucket=self.bucket_name,
                        CreateBucketConfiguration={'LocationConstraint': settings.aws_region}
                    )
                    logger.info(f"Created S3 bucket: {self.bucket_name}")
                except ClientError as create_error:
                    logger.error(f"Failed to create bucket: {create_error}")
                    raise

    async def upload_file(self, file_data: BinaryIO, object_name: str) -> str:
        """Upload file to S3"""
        try:
            self.s3_client.upload_fileobj(file_data, self.bucket_name, object_name)
            return f"s3://{self.bucket_name}/{object_name}"
        except ClientError as e:
            logger.error(f"Failed to upload file to S3: {e}")
            raise

    async def download_file(self, object_name: str) -> bytes:
        """Download file from S3"""
        try:
            response = self.s3_client.get_object(Bucket=self.bucket_name, Key=object_name)
            return response['Body'].read()
        except ClientError as e:
            logger.error(f"Failed to download file from S3: {e}")
            raise

    async def delete_file(self, object_name: str) -> bool:
        """Delete file from S3"""
        try:
            self.s3_client.delete_object(Bucket=self.bucket_name, Key=object_name)
            return True
        except ClientError as e:
            logger.error(f"Failed to delete file from S3: {e}")
            return False

    async def file_exists(self, object_name: str) -> bool:
        """Check if file exists in S3"""
        try:
            self.s3_client.head_object(Bucket=self.bucket_name, Key=object_name)
            return True
        except ClientError:
            return False

    async def get_file_url(self, object_name: str, expiration: int = 3600) -> str:
        """Generate presigned URL for S3 object"""
        try:
            url = self.s3_client.generate_presigned_url(
                'get_object',
                Params={'Bucket': self.bucket_name, 'Key': object_name},
                ExpiresIn=expiration
            )
            return url
        except ClientError as e:
            logger.error(f"Failed to generate presigned URL: {e}")
            raise